Saturn's rings aren't as peaceful as they look

Emma Woollacott, 19th March 2010

Saturn's rings aren't as neat and tidy as they appear, new observations from NASA's Cassini spacecraft show.

Chunks of material are constantly crashing into one another, creating trails of debris in their wakes, and small moons pull the ring material out of shape.

During equinox, when sunlight hits the rings exactly edge-on, Cassini observed rings that are normally flat - just tens of meters thick - being flipped up as high as the Rocky Mountains.

Cassini has also confirmed that the rings are composed mostly of water ice, with a mysterious reddish contaminant that could be rust or - more excitingly - small organic molecules similar to those found in red vegetables on Earth.

"It has been amazing to see the rings come to life before our very eyes, changing even as we watch, being colorful and taking on a tangible, 3D nature," Jeff Cuzzi, Cassini's interdisciplinary scientist for rings and dust said.

Cassini has also shown that the small moon Enceladus, not the sun or Saturn's largest moon Titan, is the biggest contributor of charged particles to Saturn's magnetic environment. These charged particles also contribute to the auroras around the poles of the planet.

"We learned from Cassini that the Saturnian magnetosphere is swimming in water," Gombosi said. "This is unique in the solar system and makes Saturn's plasma environment particularly fascinating."

But Cassini has created as many mysteries as it has solved. For example, Cassini has shown us images of occasional cannon-ball-like objects that rocket across one of the outer rings - and there's little idea about where they came from or why they so quickly disappear.

"Cassini has answered questions we were not even smart enough to ask when the mission was planned and raised a lot of new ones," Cuzzi said. "We are hot on the trail, though."